With a condensed rut, more does conceive over a shorter period, meaning fawns are also born within a smaller time frame. The influx of new fawns overwhelms predators and fewer fawns are caught, meaning MUCH higher fawn recruitment. (Credit: Guy Sagi)

A balanced herd means a short rut and happy whitetails.

by Todd Amenrud

All of us who follow sound QDM principals know that you want a balanced sex ratio and a balanced age structure for your herd. But few really understand all the reasons why. Most realize that when you have a balanced sex ratio there’s more competition amongst the bucks and that normally means better hunting and better genetics passed along. If you don’t have this balance, you’ve been missing out on intense rut activity. Besides the competition creating an environment where better genetic traits are passed along, the stability offers other big benefits to your herd, ones many managers may not realize.

How many does can a buck breed before becoming seriously depleted? According to Shorty Flees, Wilderness Whitetails in Wisconsin, a whitetail buck can breed about seven does (in the wild) before becoming severely depleted. Shorty and his family grow some of the world’s largest bucks and have paid very close attention to this issue over the years. For good reason, you obviously want to pass the genetics of a giant buck along, but you don’t want to stress the buck so his antler growth suffers. At Wilderness Whitetails, they will limit a breeder buck to procreate with about 10 does (remember this is not in the wild).

"If a buck breeds too many does and becomes rundown, it hurts his antler growth the following year. A younger buck can generally handle breeding about six does before running himself down too much. In the north where winter sets in by the time breeding season ends, bucks become very vulnerable. They cannot build their bodies back up after the rut so they try to maintain until spring. Come spring, Mother Nature diverts nutrients to rebuilding their body first. Until those needs are satisfied, the antlers get robbed of the nutrients needed to grow to their maximum potential. So bucks that come into the spring depleted are playing catch-up rather than reaping the nutritional rewards," Flees said.

With a balanced herd, the bulk of the breeding takes place over several weeks with a peak that lasts about 10 days. With too many does, the breeding may be spread out over many weeks, what some call a trickle rut. With a balance, you have an intense rut and the chase segment (what most people refer to as the peak of the rut) is extreme and concentrated over a few days of some of the best hunting you can imagine.

With an imbalanced ratio, not all the does will be bred during their first estrus cycle. A doe comes into heat for about 36-48 hours. If there’s not a buck available to breed her because he’s off tending to other does in the herd, she goes without conceiving. She will come into heat 28 days later and, if she’s not bred that time, she’ll come into heat again 28 days after that. So not only is this extremely bad for the bucks in your herd, think about the poor fawns! Rather than being born in May with the other fawns, it is born in June or even July! Do you think it’ll survive?

When the does severely outnumber the bucks, a greater number of young bucks will do some breeding. In this case, it’s possible for inferior genetics to be passed on, but this is also bad for these young bucks. Normally with older, breeding-age bucks around, through months of social interaction the younger bucks know their place and don’t attempt to breed, or at least are much less involved. Without older bucks around, the younger bucks will lose body weight and have a higher likelihood of being injured. The imbalance is bad for all deer!

Why don’t those silly bucks stop by the plot for a quick bite? For some reason, bucks just stop eating for a period of a couple weeks surrounding breeding. They don’t completely stop, but food intake with bucks in captive herds dropped approximately 90 percent during that period! So even if they have plenty of available food it really doesn’t make any difference, their intense need to breed is so extreme it consumes their life. Luckily, the does they’re searching for should be pounding your food plots so they are still a great place to hunt.

There are other reasons to balance your sex ratio. With a shorter rut, more does conceive over a shorter period, meaning fawns are dropped within a shorter time frame as well. This means MUCH higher fawn recruitment. The influx of new fawns means predators are overwhelmed with the amount of prey and fewer fawns are caught. When the rut is drawn out, fawns are born over a longer stretch and predators have a chance to hone in on more newborns.

Achieving the balance can be difficult. It can take several hunting seasons to harvest enough does to make a dent and we may have to battle natural whitetail dispersal.

Dispersal in the whitetail world typically has buck yearlings searching out a home range a fair distance away from where they were born. Some view this as Mother Nature’s way of preventing inbreeding in the herd. But the doe yearling usually takes up a home range right next to and intertwined with her mother. So, if you remove a doe, there’s a 50:50 chance that spot will be replaced by another doe. Aggressive action may be required.

You can make a difference! If you have a sound plan, things will rebound. It may take several years of aggressive doe removal, but it can be done. I’ve seen it accomplished in many states, countless times. And you will not believe the difference in hunting, especially during the rut! Mature bucks are up on their feet during the rut and the chase is intense. Your herd will also be much better off.

Todd Amenrud is the Director of Public Relations for Mossy Oak BioLogic, Editor-in-Chief of Gamekeepers, Farming for Wildlife magazine and a habitat consultant.